It has been well documented that marijuana interferes adversely with spermatogenesis in humans and rodents. Furthermore, it has been suggested that this effect is mediated locally in the testes of humans by interference with Sertoli cell function. The objective of our proposed research is two-fold; firstly, to delineate the mechanisms by which cannabinoids in marijuana affect spermatogenesis and Sertoli cell function. Secondly, to determine whether any differences in Sertoli cell function exist between pubertal and mature animals when exposed to marijuana. These objectives will be met by utilizing techniques developed in our laboratory for the isolation of human and rodent Sertoli cells. The effects of marijuana inhalation in pubertal and mature animals on markers of Sertoli cell function will be assessed, as well as examining the effect of in vitro delta-9-tetrahydrocannabinol (THC) on cultured human and animal Sertoli cells and germ cells. The markers include androgen binding protein, transferrin, inhibin, mitogen, ceruloplasmin, lactate and plasminogen activator. In addition we intend to investigate the effect of THC on transferrin receptors in human and rat germ cells. Since unlike humans, rats do not have a serum protein which binds testosterone to regulate the bound: free testosterone ratio in the blood, the rabbit will also be used as a model so that the effects of marijuana on sex hormone binding globulin (SHBG) and "free" testosterone in serum can be measured. We will measure "free" testosterone directly in serum, and measure SHBG and epidymal ABP to determine whether there is any differential effect of marijuana inhalation on the concentrations of these two closely related proteins.